Pump.



l. K. BAXTER.

PUMP.

APPLICAHON FILED JULYZT- 19x1.

Patented Nov. 9, 1915.

2 SHEETS-SHEET 2%1': A; Atty l. BAXTER.

PUMP. APPLICATION FILED JULYZI. 1911.

1,1 59,350. Patented Nov. 9, 1915.

3 2 SHEETS-SHEET 2- v vacuum, for low -rotary movement of the power 'm'eans 1nto a reclprocatory movement of the cannon.

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PUMP.

Specification of Letters Patent.

Patented 1a.; a, an.

Application filed July 27, 1911. Serial No. 640,734.

To all whom it may concern:

Be it known that I, IRVING KNo'r'r Bax- TEB, a citizen of the United States, residing at Utica, in the county of Oneida and State of New York, have invented certain new and useful Improvements in Pumps, of which the following is a specification, reference being had therein to the accompanying drawings, which form a part thereof.

My invention relates to pumps which are particularly adapted for use in vacuum or suction cleaners of a type wherein the required reduction of pressure within the apparatus is secured through the medium of traction wheels, or other rotary source of power.

In all vacuum, or suction, cleaners embodying a reciprocatory pump, with which I am familiar, whether the same be manually or power operated, there is a constant variance of pressure in the separator chamber due to a varying power in the pump actuating mechanism, with a resultant variance in the velocity of the piston stroke, a condition resulting in a corresponding variance in the effective suction at the inlet or nozzle.

The main object of the invention is to provide a vacuum or suction cleaner embodying therein a mechanism adapted to convert a developing pump piston in a manner to reciprocate said piston at uniform speed so as to create and maintain a substantially constant uniform pressure, throughout the apparatus'with a resultant constant uniform suction at the nozzle. or inlet.

A further object-is to provide a mechanism for converting a rotary movement into a reciprocatory movement, wherein the reciprocatory element will have only a direct lineal traverse and thus relieve the pump,

or other mechanism actuated thereby, from all stresses excepting the pressures resulting from "the reciprocation of the piston rod, or other member, and friction due to such reciprocatory movement.

' A still further object is to provide in a mechanism of this character, rotary means for imparting both a return and a direct reciprocation to a reciprocatory' member, and supplemental means acting upon said reciprocatory member, reciprocatory moveme t thereto "toward the end of both the direct and the return recipto impart a continued v rocation, where ordinarily the reciprocatory member would come to rest or be upon a dead center.

A still further object is to provide a mechanism of this character which will be operative in the same degree whatever the I direction of rotation of the power shaft, and wherein said power sh aft may be reversed at any time without varying the effective stroke ofthereeiprocatory member or requiring an interval of rest prior to such reversal.

A still further object is to provide a mechanism of this character which will accomplish an efiective displacement of air at the nozzle and at the same time will have said displacement substantially uniform and variable only with a variance in the speed of rotation of the power shaft.

The invention consists in such novel features of construction, and combination of parts, as are hereinafter set forth and described, and more particularly pointed out in the claims hereto appended.

-Referring to the drawings :-Figure 1 is a vertical longitudinal section of a cleaner embodying my invention; Fig. 2 is an elevation of the pump actuating mechanism; Fig.- is a plan view of said mechanism; Fig. 4 is a detailed view showing the application of a rigid nozzle attached to and movable with the device; Fig. 5 is a detailed view in vertical section of the intake Valves upon a larger scale than in Fig. 1; and Fig. 6 is a similar view of the exhaust valves on a scale similar to that of Fig. 5.

Dike letters refer to like parts throughout the several views.

In the embodiment of my invention shown in the drawings, a indicates the main frame of the machine, from which is supported the separator 72 and the pump mechan1sm,which will be more fully described hereinafter.

A detailed description of the separator mechanism will notbe herein given as such is made the subject matter of another application pending concurrently herewith, and is not material to the mechanism to which this application more particularly relates.

yZ having secured to and rotatable with it, the traction wheels 6 upon opposite sides of the frame, the motive power for actuating v Secured to the frame a is. an operating handle 0. Mounted in the frame a is an axle the pump mechanism being developed through said traction wheels and said anle.

' ordinary stufling box 71/5 To increase the effective tractive power of said wheels, they are provided with rubber, or similar, tires, e.

Supported from the frame a by means of the standards f is a bi-part diaphragm pump casing, the two parts 9 g of which inclose a reciprocatory piston plate It connected by means of the annular flexible bellows ring it with said casing. secured to the plate it by means of the ring 12 and a series of rivets, a construction which lessens the weight of the piston while securing the desired rigidity thereof. The plate it is provided with a central boss, and screw threaded therein is the piston rod k which is locked in place by means of the lock nut h. The part 9 of the pump casing is recessed at the top, as shown, to accommodate the nut 72/ and permit the maximum reciprocation of the piston rod. The lower part 7 of the casing is provided with an for the piston rod It Power is applied to the piston rod 71. by means of an open frame 2' secured thereto and having upon opposite sides thereof inwardly presented racks z" and 2' Carried by the shaft d and adapted to be alternately meshed with the racks i and i is a segmental gear j, a construction which results in a complete direct and return reciprocation of the piston rod 713, at the same rate of speed throughout, with each rotation of the shaft cl.

To relieve the piston rod 72, from all lateral strains, or in other words to limit its movement to a direct lineal traverse, I provide guide frames is supported from the frame a which frames carry antifriction rollers having beveled flanges cooperating with the outer face of each side of the frame 1', the corners of which faces are chamfered off, or beveled, to secure a close sliding fit with the rollers is and thus avoid any looseness of the frame in said bearing.

To aid in securing the frame 2' in relation to its bearings, I locate the rollers la adja cent the shaft d and the segmental gear 7' so that the stresses upon the racks z" 2' occur substantially opposite said bearing. As the frame 5 approaches either end of its reciprocatory movement, the gear j, of necessity, must pass out of mesh with one rack and into mesh with the other, unless the direction of rotation ofthe shaft d be reversed, thus affording a very slight interval of inactivity of the said gear mechanism, approaching in its character the dead center of a crank and pitman mechanism, but difiering therefrom in that between such intervals the said frame 2' will move at uniform speed with a given speed of rotation of the shaft d. In most connections of use, however, it is essential to avoid even this slight inertia at the opposite ends of'the The bellows ring h is stroke, and to accomplish this result, I pro-- vide the opposite ends of the frame 2' with laterally projecting, oppositely disposed abutments Z having inwardly presented cam surfaces, the highest point of the risers being upon the vertical radius of the shaft (Z, and mount upon said shaft 03 a rotative arm m carrying an anti-friction roller m adapted to engage the cams Z toward the end of the operative moment of the segmental gear 1' and thus impart a slight reciprocatory movement to said frame independently of said rack and gear mechanism above re ferred to. By properly determining the pitch of the rise upon the abutments l, the speed of movement imparted through said cams and said arm may be synchronized with the speed of the frame when actuated from the rack and gear mechanism, so that there will be no appreciable interval of rest or inertia at the ends of the piston strokes. This construction is, furthermore, desirable as eliminating any back lash upon the gear mechanism due to the compression of air or resistance within the pump casing and a resultant difficulty in securing a proper smootn mesh between the segmental gear and the rack upon its disengagement from one rack and its engagement with the other.

To insure a positive enmeshment and disengagement of the segmental gear 7' with the racks 2" or 5 I make the tooth next to each end tooth lower than the remaining teeth, and thus cause the segment to simultaneously mesh with two rack teeth in meshing with the rack, or pass freely from the short tooth when disengaging said rack. To further aid in accomplishing this object, the end teeth of the segmental gear j are shortened.

The two parts 9 g of the pump casing are made of a thin casting and each part is provided with an intake and an exhaust port of large area so as to secure fairly free action of the pump, through minimizing the pressure within same; These two sec tions are bolted firmly upon the outer edge of the bellows ring it which acts as a packing between the two parts, to form an air tight joint without the aid of solder or other metallic binding means. A

The intake ports are arranged in ducts n 11. adapted to be clamped against'correspending ducts in the separator 12, as shown in Fig. l of the drawings. To secure a tight joint between the two sections of each of these ducts, I interpose between same leather washers 0 0, a portion of the center of each of which is cut so as to leave acentral flexible flap to which is secured a rigid valve block 12 or ;12 adapted to act as a. weight for automatically closing the valve by gravity, the said flap seating upon the inner edge of the metal duct leading from the dust tank. The ducts n n are shaped as shown, to seance for the free oscillatory movement of the valve blocks.

The parts 9 g of the pump casing are recessed about the exhaust port and fitted to each of said recessed portions is a leather disk, the upper end of which is secured by means 'of a screw and a metal plate to said casing. Mounted upon said leather disk is a weighted valve block, theupper edge of which is spaced away from said securing means sufliciently to allow the leather to act as a hinge for the block, thus forming a simple and effective exhaust mechanism for the pump.

To permit the effective operation of the pump, by tractive force, it is desirable to support the forward end of the cleaner independently of the operating handle so as to reliex'e the operator of the effort incidental to supportingv said end. This supporting means, when it is desired to clean floor covering, may be the cleaner nozzle q itself, as shown in Fig. 4 of the drawings, but when it is desired to have two persons operate the device, as is necessary when cleaning walls, room draperies, furniture, etc., this supporting means comprises the coupling member 1* having an upwardly turned outlet in which the end of the flexible tubes carrying the cleaner nozzle may beattached, said coupling member also having a forwardly and downwardly projecting fork in which are mounted wheels or rollers u. It will thus be observed that whether the cleaning nozzle contacts with the floor or whether the wheels or.rollers u are used, the forward end of the apparatus is supported from the floor, thus securing the perfect equilibrium of the apparatus and simplifying the opera- 7 tion thereof.

The support for the forward end of the apparatus is detachably connected to the separator by means of pivoted clamp screws upon the separator, and forks upon the support, so that these parts are interchangeable to adapt one apparatus for use by either a single person or by two persons, as above referred to. e

The operationofthe herein described apparatus is substantially as follows :When it is desired to create a partial vacuum within the separator. or a reduction of the pressure therein, suflicient to create an effective suction at the cleaning nozzle, it is merely necessary to roll the apparatus over the surface to be cleaned, when the supportshown in Fig. 4 is used, or roll it adjacent to the object to be cleaned when the support shown in Fig. 1 is used, or if desired, the apparatus may be rolled back and forth. With the movement of the shaft (1, through the traction wheels, the segmental gear 7' is rotated therewith and through either rack 11' or '5 lowers or raises the frame 71 and thus imparts a direct reciprocatory movement to the piston rod 71?. If the apparatus is moved at uniform speed,the peripheral velocity of the segmental gear j will be uniform and the movement of the racks i i in either direction will be constant and uniform with a resultant uniform displacement ofair by the pump piston, thus maintaining a, condition within the pump wherein the indicated pressure will be low and re.nain so without substantial v'ariance. This condition is very desirable in vacuum cleaners because in the use of such, variable low pressure within the separator results in an unequal capacity at the nozzle, and a loss of efficiency due to the necessity for close inspection. and repeated applications of the nozzle tosuch portions of the objectbeing cleaned Where the suction was not sufficiently great to thoroughly remove the dust and dirt. If the apparatus be reciprocated, the reciprocation of the rod 72. will result from the enmeshment of the gear with one rack 71' or i only, the stroke or partial stroke of the piston being at uniform speed, without an appreciable interval of rest, or inertia, upon the reversal of direction of movement. If, however, the apparatus be moved continuously in one direction, the segmental or mutilated gear 7' reciprocates the frame 11 to a degree determined by the interval of enmeshment of said segmental gear with one rack. 11' or 71 and when the piston rodi has reachedthe limit of its direct reciprocation under said rack and gear mechanism, said gear will automatically disengage itself from the rack 71 or i and through its continued rotation will enmesh with the oppositely disposed rack and reverse the direc- 'tion of movement of the piston rod k thus converting the rotary movement of the shaft (1 into a reciprocatory movement of the frame 71 and the piston rod 71. or other agent to which power is applied through the frame 2'. It' will be observed that if the speed. of rotation of the shaft dbe uniform, the speed of movement of the frame 11 will also be uniform. When used with a suction pump, however, the-pressure against which the pist'on acts will have a constant tendency to react upon. the frame 2' ma manner which might result in back lash between'the gear j and either rack 13 or 2", and disturb the relation of the said gear and said rack at the moment of the disengagement of one with the other, in a degree to interfere with the proper mesh of said gear with the other rack, and it is to avoid this diflicultyqthat the arm 'm. and cams Z are provided. This arm, projecting as it does along the central radius of the segmental gear 9', will through its engagement with either cam l not only impart a reciprocatory movement to said prevent any such looseness of the frame 2' as would subject the piston rod k to any lateral strains which would tend to develop friction or rack the pump structure. The

detailed structure of the pump casing and the interchangeable supporting means for the forward end of the apparatus, are desirable structural features, the operation of ,which isapparent from the foregoing description.

It is not my intention to limit the invention in its broader aspects-to the details of construction set forth in the accompanying drawings, it being apparent that such may bemodified without departing from the spirit or scope of the invention.

The mechanism herein described for converting the rotary movement of the shaft (Z into a reciprocatory movement, I believe to be broadly new, and I intend to claim such broadly.

Having described my invention, what I claim as new and desire to have protected by Letters Patent, is

1. In a pump for vacuum cleaning purposes, the combination with a pumping chamber of a double acting reciprocating member therein, a rotary driving shaft and connections between said shaft and reciproeating member comprising means whereby constant reciprocatory motion at uniform speed is imparted to the reciprocating member for a uniform rate of rotation of the driving means, said means comprising oppositely disposed internally-presented racks carried by said reciprocating member, a segmental gear carried by said rotary driving means and adapted to alternately engage said racks, means for continuing the motion of the reciprocating member toward the end of each stroke as the rotating segmental gear is passing out of mesh with one rack and into meshv with the other, and means for keeping said racks and segmental gear constantly inproper relative positions.

' 2. In a "pump for vacuum cleaning purposes, the combination with a pumping chamber of a double acting reciprocating member therein, a rotary driving shaft and 0 connections between said shaft and reciprocating member comprising means whereby constant reciprocatory motion at uniform speed is imparted to the reciprocating member for a uniform rate of rotation of the driving means, said means comprising oppositely disposed internally presented racks and oppositely disposed cam surfaces carried by said reciprocating member, a segmental gear carried by, the rotary driving means mounted between said racks and adapted to alternately engage them, and an arm carried by the driving means and adapted to alternately engage the cam surfaces near the end of each stroke of the reciprocating member.

3. In a pump for vacuum cleaning purposes, the combination with a pumping chamber of a double acting reciprocating member therein, a rotary driving shaft and connections between said shaft and reciprocating member comprising means whereby constant reciprocatory motion at a uniform speed is imparted to the reciprocating member for a uniform rate of rotation of the driving means, oppositely disposed inter nally presented racks carried by the reciprocating member, a segmental gear carried by said rotary driving means and adapted to alternately engage them, and means for continuing the reciprocating motion of the reciprocating member toward the end of each stroke while the gear is out of engagement with the racks.

4. In a pump for vacuum cleaning purposes, the (-omhinat-ionwith a pumping chamber of a double acting reciprocating member therein. a rotary driving shaft and connections between said shaft and reciprocating member comprising means whereby constant reciprocatory motion at uniform speed is imparted to the reciprocating mem-- -.ber for a uniform rate of rotation of the drivmg means, sald means comprising oppositely disposed racks carried by the reciprocating member, a segmental gear carried by the driving means and adapted to alternately engage the racks, means for continuing the reciprocating motion of the reciprocating member toward the end of each stroke and for lifting the racks clear of said gear and maintaining them in proper relative positions to it While the said gear is out of engagement with theracks.

In witness whereof, I have hereunto affixed my signature in the presence of two subscribing witnesses, this 22nd day of July, 1911.

IRVING KNOTT BAXTER.

Witnesses:

W. H. MGLEER, EUGENE WENING. 

